It's not possible without client-side patch on executable/UniMod level, you are right. But, if you look at my UniMod monster arena maps, you can see that you can use some player control keys (that are already mapped and handled by Nox, like spacebar=jump, taunts and etc.) to do things like that without any client-side modifications, there are some restrictions though.

Retired Nox hacker enthusiast. One of those who made latest Map Editor.